1. Field of the Invention(s)
The present invention(s) generally relate to waveguide circulators. More particularly, the invention(s) relate to systems and methods for stacked waveguide circulators.
2. Description of Related Art
Typical point-to-point wireless communications systems commonly combine transmit and receive signals to and from antennas using antenna combining units of some form. In some examples, a single transmit signal can be combined with a single receive signal, multiple transmit signals can be combined together, multiple receive signals can be combined together, and multiple transmit signals can be combined with multiple receive signals. Combining of signals allows for sharing of expensive antenna systems by multiple transmitters and/or receivers, either for multiple data paths and/or for signal protection.
There are several common techniques to combine signals in the prior art. For example, a diplexer may combine a single transmit signal with a single receive signal. Unfortunately, diplexers only allow one transmit and one receive signal to be combined. Further, diplexers allow for little flexibility and few options for expansion. In another example, filters with coaxial connectors connected with coaxial circulators and coaxial cables may be used to combine signals. The disadvantage of using coaxial cable and coaxial circulators to connect filters is the introduction of power loss into the path. Another technique to combine signals is to use filters with waveguide flanges which may be connected together with waveguide circulators in the prior art.
FIG. 1 depicts a waveguide circulator 100 in the prior art. Typically, waveguide circulators 100 include three ports including one port per side of the waveguide circulator 100. The waveguide circulator 100 has three ports 102, 104, and 106 including one port on each of three sides. The waveguide circulator 100 also has three flanges 108, 110, and 116 around each port 102, 104, and 106, respectively. The ports 102, 104, and 106 are used for transferring wave energy in a non-reciprocal manner, such that when wave energy is fed into one port, it is transferred to the next port only. In order to enable the non-reciprocal energy transfer, waveguide circulators include ferrite resonators to which are applied a magnetic field via one or more magnets or electromagnets. The flanges are used to couple the waveguide circulator 100 with waveguides and/or filters. Unfortunately, waveguide circulators 100 and waveguide fittings used to connect filters with waveguide flanges tend to be large and consume considerable space. In order to combine a transmitter and a receiver to a waveguide circulator 100, the connection to the transmitter must be at a right angle or 180 degrees to the connection to the receiver. As such, it is difficult to combine multiple waveguide circulators with multiple filters, transmitters, and/or receivers in a limited space.